Once a fundraising juggernaut helmed by Newt Gingrich, American Solutions for Winning the Future has closed its doors.

The 527 group’s fundraising started to lag as soon as the former House speaker launched his White House bid in May, said one former staffer. Two months later, it was forced to quietly shut down operations.

American Solutions, founded by Gingrich in 2007, vacated its K Street offices and the last six employees were laid off on July 7.

“This organization was built by Newt,” said the staffer. “A lot of it was built on his image, and American Solutions didn’t have its own brand at the time when he broke from the organization and started running for president.”

So when Gingrich stumbled, so did American Solutions.

“Just as he started struggling from those early campaign mess-ups, it was a situation where American Solutions was in similar trouble and we weren’t in a position to ride those out,” the staffer said.

The news arrives just as Gingrich enters the fall season of campaigning. Forced to sever ties with his main political committee under federal election law, the candidate has been working the phones — and his old donor base — to dig his campaign out of its more than $1 million in debt.

In the first half of the year, American Solutions spent $2.9 million but raised only $2.4 million, according to a Aug. 18 filing with the Internal Revenue Service.

The group’s PAC, also named American Solutions, closed on Aug. 8. By the end of June, it had spent all of its cash, according to Federal Election Commission filings.

It was a dramatic slowdown from the heyday of the 2010 election cycle, when American Solutions became the biggest spender among 527 groups, according to a Center for Responsive Politics analysis.

Over the past five years, American Solutions collected more than $52 million from big-name donors — like Las Vegas casino mogul Sheldon Adelson and coal giant Peabody Energy — who could give unlimited funds.

Initially, employees believed American Solutions could succeed without its chairman. It made a name for itself in the conservative policy world with the widespread promotion of “Drill Here, Drill Now,” a campaign advocating increased domestic energy production and fewer federal regulations, and cultivated “one of the most responsive email lists out there,” the staffer said.

A few American Solutions operatives had migrated over to the presidential campaign when Gingrich announced. R.C. Hammond, a former spokesman for American Solutions, moved over, along with several fundraising operatives.